01 - Combine garlic, rosemary, thyme, Dijon mustard, olive oil, salt, and black pepper in a small bowl, mixing thoroughly to form a cohesive paste.
02 - Pat the rack of lamb completely dry with paper towels, then rub the marinade evenly over all surfaces, ensuring thorough coverage.
03 - Place the coated lamb in a dish or resealable bag and refrigerate for at least 1 hour, up to overnight for intensified flavor penetration.
04 - Remove the lamb from refrigeration 30 minutes before cooking to reach room temperature. Preheat oven to 425°F.
05 - Heat 1 tablespoon olive oil in an ovenproof skillet over medium-high heat. Sear the lamb for 2–3 minutes per side until a golden-brown crust forms.
06 - Transfer the skillet to the preheated oven. Roast for 15–20 minutes for medium-rare (internal temperature 125–130°F), adjusting time for preferred doneness.
07 - Remove from oven and tent loosely with aluminum foil. Allow the meat to rest for 10 minutes, permitting juices to redistribute throughout the meat.
08 - Slice between bones into individual chops. Sprinkle with flaky sea salt immediately before serving.